.wrapper {
  padding: 16px;
}

.playground {
  margin-bottom: 16px;
  border: 1px solid #ccc;
  padding: 16px;
  border-radius: 5px;
}

.code {
  margin-bottom: 10px;
}
.box1 {
  width: 100px;
  background-color: coral;
  color: #fff;
}
@keyframes width {
  50%{
    width: 300px;
  }
}